658 lines
29 KiB
Groff
Executable File
658 lines
29 KiB
Groff
Executable File
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.\" ========================================================================
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.\"
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.IX Title "EVP_DIGESTINIT 3"
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.TH EVP_DIGESTINIT 3 "2020-03-02" "3.0.0-dev" "OpenSSL"
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.\" For nroff, turn off justification. Always turn off hyphenation; it makes
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.\" way too many mistakes in technical documents.
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.if n .ad l
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.nh
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.SH "NAME"
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EVP_MD_fetch, EVP_MD_up_ref, EVP_MD_free,
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EVP_MD_get_params, EVP_MD_gettable_params,
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EVP_MD_CTX_new, EVP_MD_CTX_reset, EVP_MD_CTX_free, EVP_MD_CTX_copy,
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EVP_MD_CTX_copy_ex, EVP_MD_CTX_ctrl,
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EVP_MD_CTX_set_params, EVP_MD_CTX_get_params,
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EVP_MD_settable_ctx_params, EVP_MD_gettable_ctx_params,
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EVP_MD_CTX_settable_params, EVP_MD_CTX_gettable_params,
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EVP_MD_CTX_set_flags, EVP_MD_CTX_clear_flags, EVP_MD_CTX_test_flags,
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EVP_Digest, EVP_DigestInit_ex, EVP_DigestInit, EVP_DigestUpdate,
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EVP_DigestFinal_ex, EVP_DigestFinalXOF, EVP_DigestFinal,
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EVP_MD_is_a, EVP_MD_name, EVP_MD_number, EVP_MD_names_do_all, EVP_MD_provider,
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EVP_MD_type, EVP_MD_pkey_type, EVP_MD_size, EVP_MD_block_size, EVP_MD_flags,
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EVP_MD_CTX_name,
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EVP_MD_CTX_md, EVP_MD_CTX_type, EVP_MD_CTX_size, EVP_MD_CTX_block_size,
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EVP_MD_CTX_md_data, EVP_MD_CTX_update_fn, EVP_MD_CTX_set_update_fn,
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EVP_md_null,
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EVP_get_digestbyname, EVP_get_digestbynid, EVP_get_digestbyobj,
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EVP_MD_CTX_pkey_ctx, EVP_MD_CTX_set_pkey_ctx,
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EVP_MD_do_all_provided
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\&\- EVP digest routines
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.SH "SYNOPSIS"
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.IX Header "SYNOPSIS"
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.Vb 1
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\& #include <openssl/evp.h>
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\&
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\& EVP_MD *EVP_MD_fetch(OPENSSL_CTX *ctx, const char *algorithm,
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\& const char *properties);
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\& int EVP_MD_up_ref(EVP_MD *md);
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\& void EVP_MD_free(EVP_MD *md);
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\& int EVP_MD_get_params(const EVP_MD *digest, OSSL_PARAM params[]);
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\& const OSSL_PARAM *EVP_MD_gettable_params(const EVP_MD *digest);
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\& EVP_MD_CTX *EVP_MD_CTX_new(void);
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\& int EVP_MD_CTX_reset(EVP_MD_CTX *ctx);
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\& void EVP_MD_CTX_free(EVP_MD_CTX *ctx);
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\& void EVP_MD_CTX_ctrl(EVP_MD_CTX *ctx, int cmd, int p1, void* p2);
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\& int EVP_MD_CTX_get_params(EVP_MD_CTX *ctx, OSSL_PARAM params[]);
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\& int EVP_MD_CTX_set_params(EVP_MD_CTX *ctx, const OSSL_PARAM params[]);
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\& const OSSL_PARAM *EVP_MD_settable_ctx_params(const EVP_MD *md);
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\& const OSSL_PARAM *EVP_MD_gettable_ctx_params(const EVP_MD *md);
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\& const OSSL_PARAM *EVP_MD_CTX_settable_params(EVP_MD_CTX *ctx);
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\& const OSSL_PARAM *EVP_MD_CTX_gettable_params(EVP_MD_CTX *ctx);
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\& void EVP_MD_CTX_set_flags(EVP_MD_CTX *ctx, int flags);
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\& void EVP_MD_CTX_clear_flags(EVP_MD_CTX *ctx, int flags);
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\& int EVP_MD_CTX_test_flags(const EVP_MD_CTX *ctx, int flags);
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\&
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\& int EVP_Digest(const void *data, size_t count, unsigned char *md,
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\& unsigned int *size, const EVP_MD *type, ENGINE *impl);
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\& int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
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\& int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt);
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\& int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s);
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\& int EVP_DigestFinalXOF(EVP_MD_CTX *ctx, unsigned char *md, size_t len);
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\&
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\& int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in);
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\&
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\& int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type);
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\& int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s);
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\&
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\& int EVP_MD_CTX_copy(EVP_MD_CTX *out, EVP_MD_CTX *in);
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\&
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\& const char *EVP_MD_name(const EVP_MD *md);
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\& int EVP_MD_number(const EVP_MD *md);
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\& int EVP_MD_is_a(const EVP_MD *md, const char *name);
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\& void EVP_MD_names_do_all(const EVP_MD *md,
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\& void (*fn)(const char *name, void *data),
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\& void *data);
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\& const OSSL_PROVIDER *EVP_MD_provider(const EVP_MD *md);
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\& int EVP_MD_type(const EVP_MD *md);
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\& int EVP_MD_pkey_type(const EVP_MD *md);
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\& int EVP_MD_size(const EVP_MD *md);
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\& int EVP_MD_block_size(const EVP_MD *md);
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\& unsigned long EVP_MD_flags(const EVP_MD *md);
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\&
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\& const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
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\& const char *EVP_MD_CTX_name(const EVP_MD_CTX *ctx);
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\& int EVP_MD_CTX_size(const EVP_MD_CTX *ctx);
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\& int EVP_MD_CTX_block_size(const EVP_MD_CTX *ctx);
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\& int EVP_MD_CTX_type(const EVP_MD_CTX *ctx);
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\& void *EVP_MD_CTX_md_data(const EVP_MD_CTX *ctx);
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\& int (*EVP_MD_CTX_update_fn(EVP_MD_CTX *ctx))(EVP_MD_CTX *ctx,
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\& const void *data, size_t count);
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\& void EVP_MD_CTX_set_update_fn(EVP_MD_CTX *ctx,
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\& int (*update)(EVP_MD_CTX *ctx,
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\& const void *data, size_t count));
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\&
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\& const EVP_MD *EVP_md_null(void);
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\&
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\& const EVP_MD *EVP_get_digestbyname(const char *name);
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\& const EVP_MD *EVP_get_digestbynid(int type);
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\& const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o);
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\&
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\& EVP_PKEY_CTX *EVP_MD_CTX_pkey_ctx(const EVP_MD_CTX *ctx);
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\& void EVP_MD_CTX_set_pkey_ctx(EVP_MD_CTX *ctx, EVP_PKEY_CTX *pctx);
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\&
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\& void EVP_MD_do_all_provided(OPENSSL_CTX *libctx,
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\& void (*fn)(EVP_MD *mac, void *arg),
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\& void *arg);
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.Ve
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.SH "DESCRIPTION"
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.IX Header "DESCRIPTION"
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The \s-1EVP\s0 digest routines are a high level interface to message digests,
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and should be used instead of the digest-specific functions.
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.PP
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The \fB\s-1EVP_MD\s0\fR type is a structure for digest method implementation.
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.IP "\fIEVP_MD_fetch()\fR" 4
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.IX Item "EVP_MD_fetch()"
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Fetches the digest implementation for the given \fBalgorithm\fR from any
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provider offering it, within the criteria given by the \fBproperties\fR.
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See \*(L"Fetching algorithms\*(R" in \fIprovider\fR\|(7) for further information.
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.Sp
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The returned value must eventually be freed with \fIEVP_MD_free()\fR.
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.Sp
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Fetched \fB\s-1EVP_MD\s0\fR structures are reference counted.
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.IP "\fIEVP_MD_up_ref()\fR" 4
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.IX Item "EVP_MD_up_ref()"
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Increments the reference count for an \fB\s-1EVP_MD\s0\fR structure.
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.IP "\fIEVP_MD_free()\fR" 4
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.IX Item "EVP_MD_free()"
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Decrements the reference count for the fetched \fB\s-1EVP_MD\s0\fR structure.
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If the reference count drops to 0 then the structure is freed.
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.IP "\fIEVP_MD_CTX_new()\fR" 4
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.IX Item "EVP_MD_CTX_new()"
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Allocates and returns a digest context.
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.IP "\fIEVP_MD_CTX_reset()\fR" 4
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.IX Item "EVP_MD_CTX_reset()"
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Resets the digest context \fBctx\fR. This can be used to reuse an already
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existing context.
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.IP "\fIEVP_MD_CTX_free()\fR" 4
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.IX Item "EVP_MD_CTX_free()"
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Cleans up digest context \fBctx\fR and frees up the space allocated to it.
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.IP "\fIEVP_MD_CTX_ctrl()\fR" 4
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.IX Item "EVP_MD_CTX_ctrl()"
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This is a legacy method. \fIEVP_MD_CTX_set_params()\fR and \fIEVP_MD_CTX_get_params()\fR
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is the mechanism that should be used to set and get parameters that are used by
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providers.
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Performs digest-specific control actions on context \fBctx\fR. The control command
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is indicated in \fBcmd\fR and any additional arguments in \fBp1\fR and \fBp2\fR.
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\&\fIEVP_MD_CTX_ctrl()\fR must be called after \fIEVP_DigestInit_ex()\fR. Other restrictions
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may apply depending on the control type and digest implementation.
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See \*(L"\s-1CONTROLS\s0\*(R" below for more information.
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.IP "\fIEVP_MD_get_params()\fR" 4
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.IX Item "EVP_MD_get_params()"
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Retrieves the requested list of \fBparams\fR from a \s-1MD\s0 \fBmd\fR.
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See \*(L"\s-1PARAMETERS\s0\*(R" below for more information.
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.IP "\fIEVP_MD_CTX_get_params()\fR" 4
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.IX Item "EVP_MD_CTX_get_params()"
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Retrieves the requested list of \fBparams\fR from a \s-1MD\s0 context \fBctx\fR.
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See \*(L"\s-1PARAMETERS\s0\*(R" below for more information.
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.IP "\fIEVP_MD_CTX_set_params()\fR" 4
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.IX Item "EVP_MD_CTX_set_params()"
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Sets the list of \fBparams\fR into a \s-1MD\s0 context \fBctx\fR.
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See \*(L"\s-1PARAMETERS\s0\*(R" below for more information.
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.IP "\fIEVP_MD_gettable_params()\fR, \fIEVP_MD_gettable_ctx_params()\fR, \fIEVP_MD_settable_ctx_params()\fR, \fIEVP_MD_CTX_gettable_params()\fR, \fIEVP_MD_CTX_settable_params()\fR" 4
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.IX Item "EVP_MD_gettable_params(), EVP_MD_gettable_ctx_params(), EVP_MD_settable_ctx_params(), EVP_MD_CTX_gettable_params(), EVP_MD_CTX_settable_params()"
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Get a \fB\s-1OSSL_PARAM\s0\fR array that describes the retrievable and settable
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parameters. \fIEVP_MD_gettable_params()\fR returns parameters that can be used with
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\&\fIEVP_MD_get_params()\fR. \fIEVP_MD_gettable_ctx_params()\fR and
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\&\fIEVP_MD_CTX_gettable_params()\fR return parameters that can be used with
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\&\fIEVP_MD_CTX_get_params()\fR. \fIEVP_MD_settable_ctx_params()\fR and
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\&\fIEVP_MD_CTX_settable_params()\fR return parameters that can be used with
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\&\fIEVP_MD_CTX_set_params()\fR.
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See \s-1\fIOSSL_PARAM\s0\fR\|(3) for the use of \fB\s-1OSSL_PARAM\s0\fR as parameter descriptor.
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.IP "\fIEVP_MD_CTX_set_flags()\fR, \fIEVP_MD_CTX_clear_flags()\fR, \fIEVP_MD_CTX_test_flags()\fR" 4
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.IX Item "EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags(), EVP_MD_CTX_test_flags()"
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Sets, clears and tests \fBctx\fR flags. See \*(L"\s-1FLAGS\s0\*(R" below for more information.
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.IP "\fIEVP_Digest()\fR" 4
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.IX Item "EVP_Digest()"
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A wrapper around the Digest Init_ex, Update and Final_ex functions.
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Hashes \fBcount\fR bytes of data at \fBdata\fR using a digest \fBtype\fR from \s-1ENGINE\s0
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\&\fBimpl\fR. The digest value is placed in \fBmd\fR and its length is written at \fBsize\fR
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if the pointer is not \s-1NULL\s0. At most \fB\s-1EVP_MAX_MD_SIZE\s0\fR bytes will be written.
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If \fBimpl\fR is \s-1NULL\s0 the default implementation of digest \fBtype\fR is used.
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.IP "\fIEVP_DigestInit_ex()\fR" 4
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.IX Item "EVP_DigestInit_ex()"
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Sets up digest context \fBctx\fR to use a digest \fBtype\fR.
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\&\fBtype\fR is typically supplied by a function such as \fIEVP_sha1()\fR, or a
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value explicitly fetched with \fIEVP_MD_fetch()\fR.
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.Sp
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If \fBimpl\fR is non-NULL, its implementation of the digest \fBtype\fR is used if
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there is one, and if not, the default implementation is used.
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.IP "\fIEVP_DigestUpdate()\fR" 4
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.IX Item "EVP_DigestUpdate()"
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Hashes \fBcnt\fR bytes of data at \fBd\fR into the digest context \fBctx\fR. This
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function can be called several times on the same \fBctx\fR to hash additional
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data.
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.IP "\fIEVP_DigestFinal_ex()\fR" 4
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.IX Item "EVP_DigestFinal_ex()"
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Retrieves the digest value from \fBctx\fR and places it in \fBmd\fR. If the \fBs\fR
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parameter is not \s-1NULL\s0 then the number of bytes of data written (i.e. the
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length of the digest) will be written to the integer at \fBs\fR, at most
|
|
\&\fB\s-1EVP_MAX_MD_SIZE\s0\fR bytes will be written. After calling \fIEVP_DigestFinal_ex()\fR
|
|
no additional calls to \fIEVP_DigestUpdate()\fR can be made, but
|
|
\&\fIEVP_DigestInit_ex()\fR can be called to initialize a new digest operation.
|
|
.IP "\fIEVP_DigestFinalXOF()\fR" 4
|
|
.IX Item "EVP_DigestFinalXOF()"
|
|
Interfaces to extendable-output functions, XOFs, such as \s-1SHAKE128\s0 and \s-1SHAKE256\s0.
|
|
It retrieves the digest value from \fBctx\fR and places it in \fBlen\fR\-sized <B>md.
|
|
After calling this function no additional calls to \fIEVP_DigestUpdate()\fR can be
|
|
made, but \fIEVP_DigestInit_ex()\fR can be called to initialize a new operation.
|
|
.IP "\fIEVP_MD_CTX_copy_ex()\fR" 4
|
|
.IX Item "EVP_MD_CTX_copy_ex()"
|
|
Can be used to copy the message digest state from \fBin\fR to \fBout\fR. This is
|
|
useful if large amounts of data are to be hashed which only differ in the last
|
|
few bytes.
|
|
.IP "\fIEVP_DigestInit()\fR" 4
|
|
.IX Item "EVP_DigestInit()"
|
|
Behaves in the same way as \fIEVP_DigestInit_ex()\fR except it always uses the
|
|
default digest implementation and calls \fIEVP_MD_CTX_reset()\fR.
|
|
.IP "\fIEVP_DigestFinal()\fR" 4
|
|
.IX Item "EVP_DigestFinal()"
|
|
Similar to \fIEVP_DigestFinal_ex()\fR except the digest context \fBctx\fR is
|
|
automatically cleaned up.
|
|
.IP "\fIEVP_MD_CTX_copy()\fR" 4
|
|
.IX Item "EVP_MD_CTX_copy()"
|
|
Similar to \fIEVP_MD_CTX_copy_ex()\fR except the destination \fBout\fR does not have to
|
|
be initialized.
|
|
.IP "\fIEVP_MD_is_a()\fR" 4
|
|
.IX Item "EVP_MD_is_a()"
|
|
Returns 1 if \fImd\fR is an implementation of an algorithm that's
|
|
identifiable with \fIname\fR, otherwise 0.
|
|
.Sp
|
|
If \fImd\fR is a legacy digest (it's the return value from the likes of
|
|
\&\fIEVP_sha256()\fR rather than the result of an \fIEVP_MD_fetch()\fR), only cipher
|
|
names registered with the default library context (see
|
|
\&\s-1\fIOPENSSL_CTX\s0\fR\|(3)) will be considered.
|
|
.IP "\fIEVP_MD_number()\fR" 4
|
|
.IX Item "EVP_MD_number()"
|
|
Returns the internal dynamic number assigned to the \fImd\fR. This is
|
|
only useful with fetched \fB\s-1EVP_MD\s0\fRs.
|
|
.IP "\fIEVP_MD_name()\fR, \fIEVP_MD_CTX_name()\fR" 4
|
|
.IX Item "EVP_MD_name(), EVP_MD_CTX_name()"
|
|
Return the name of the given message digest. For fetched message
|
|
digests with multiple names, only one of them is returned; it's
|
|
recommended to use \fIEVP_MD_names_do_all()\fR instead.
|
|
.IP "\fIEVP_MD_names_do_all()\fR" 4
|
|
.IX Item "EVP_MD_names_do_all()"
|
|
Traverses all names for the \fImd\fR, and calls \fIfn\fR with each name and
|
|
\&\fIdata\fR. This is only useful with fetched \fB\s-1EVP_MD\s0\fRs.
|
|
.IP "\fIEVP_MD_provider()\fR" 4
|
|
.IX Item "EVP_MD_provider()"
|
|
Returns an \fB\s-1OSSL_PROVIDER\s0\fR pointer to the provider that implements the given
|
|
\&\fB\s-1EVP_MD\s0\fR.
|
|
.IP "\fIEVP_MD_size()\fR, \fIEVP_MD_CTX_size()\fR" 4
|
|
.IX Item "EVP_MD_size(), EVP_MD_CTX_size()"
|
|
Return the size of the message digest when passed an \fB\s-1EVP_MD\s0\fR or an
|
|
\&\fB\s-1EVP_MD_CTX\s0\fR structure, i.e. the size of the hash.
|
|
.IP "\fIEVP_MD_block_size()\fR, \fIEVP_MD_CTX_block_size()\fR" 4
|
|
.IX Item "EVP_MD_block_size(), EVP_MD_CTX_block_size()"
|
|
Return the block size of the message digest when passed an \fB\s-1EVP_MD\s0\fR or an
|
|
\&\fB\s-1EVP_MD_CTX\s0\fR structure.
|
|
.IP "\fIEVP_MD_type()\fR, \fIEVP_MD_CTX_type()\fR" 4
|
|
.IX Item "EVP_MD_type(), EVP_MD_CTX_type()"
|
|
Return the \s-1NID\s0 of the \s-1OBJECT\s0 \s-1IDENTIFIER\s0 representing the given message digest
|
|
when passed an \fB\s-1EVP_MD\s0\fR structure. For example, \f(CW\*(C`EVP_MD_type(EVP_sha1())\*(C'\fR
|
|
returns \fBNID_sha1\fR. This function is normally used when setting \s-1ASN1\s0 OIDs.
|
|
.IP "\fIEVP_MD_CTX_md_data()\fR" 4
|
|
.IX Item "EVP_MD_CTX_md_data()"
|
|
Return the digest method private data for the passed \fB\s-1EVP_MD_CTX\s0\fR.
|
|
The space is allocated by OpenSSL and has the size originally set with
|
|
\&\fIEVP_MD_meth_set_app_datasize()\fR.
|
|
.IP "\fIEVP_MD_CTX_md()\fR" 4
|
|
.IX Item "EVP_MD_CTX_md()"
|
|
Returns the \fB\s-1EVP_MD\s0\fR structure corresponding to the passed \fB\s-1EVP_MD_CTX\s0\fR. This
|
|
will be the same \fB\s-1EVP_MD\s0\fR object originally passed to \fIEVP_DigestInit_ex()\fR (or
|
|
other similar function) when the \s-1EVP_MD_CTX\s0 was first initialised. Note that
|
|
where explicit fetch is in use (see \fIEVP_MD_fetch\fR\|(3)) the value returned from
|
|
this function will not have its reference count incremented and therefore it
|
|
should not be used after the \s-1EVP_MD_CTX\s0 is freed.
|
|
.IP "\fIEVP_MD_CTX_set_update_fn()\fR" 4
|
|
.IX Item "EVP_MD_CTX_set_update_fn()"
|
|
Sets the update function for \fBctx\fR to \fBupdate\fR.
|
|
This is the function that is called by EVP_DigestUpdate. If not set, the
|
|
update function from the \fB\s-1EVP_MD\s0\fR type specified at initialization is used.
|
|
.IP "\fIEVP_MD_CTX_update_fn()\fR" 4
|
|
.IX Item "EVP_MD_CTX_update_fn()"
|
|
Returns the update function for \fBctx\fR.
|
|
.IP "\fIEVP_MD_flags()\fR" 4
|
|
.IX Item "EVP_MD_flags()"
|
|
Returns the \fBmd\fR flags. Note that these are different from the \fB\s-1EVP_MD_CTX\s0\fR
|
|
ones. See \fIEVP_MD_meth_set_flags\fR\|(3) for more information.
|
|
.IP "\fIEVP_MD_pkey_type()\fR" 4
|
|
.IX Item "EVP_MD_pkey_type()"
|
|
Returns the \s-1NID\s0 of the public key signing algorithm associated with this
|
|
digest. For example \fIEVP_sha1()\fR is associated with \s-1RSA\s0 so this will return
|
|
\&\fBNID_sha1WithRSAEncryption\fR. Since digests and signature algorithms are no
|
|
longer linked this function is only retained for compatibility reasons.
|
|
.IP "\fIEVP_md_null()\fR" 4
|
|
.IX Item "EVP_md_null()"
|
|
A \*(L"null\*(R" message digest that does nothing: i.e. the hash it returns is of zero
|
|
length.
|
|
.IP "\fIEVP_get_digestbyname()\fR, \fIEVP_get_digestbynid()\fR, \fIEVP_get_digestbyobj()\fR" 4
|
|
.IX Item "EVP_get_digestbyname(), EVP_get_digestbynid(), EVP_get_digestbyobj()"
|
|
Returns an \fB\s-1EVP_MD\s0\fR structure when passed a digest name, a digest \fB\s-1NID\s0\fR or an
|
|
\&\fB\s-1ASN1_OBJECT\s0\fR structure respectively.
|
|
.IP "\fIEVP_MD_CTX_pkey_ctx()\fR" 4
|
|
.IX Item "EVP_MD_CTX_pkey_ctx()"
|
|
Returns the \fB\s-1EVP_PKEY_CTX\s0\fR assigned to \fBctx\fR. The returned pointer should not
|
|
be freed by the caller.
|
|
.IP "\fIEVP_MD_CTX_set_pkey_ctx()\fR" 4
|
|
.IX Item "EVP_MD_CTX_set_pkey_ctx()"
|
|
Assigns an \fB\s-1EVP_PKEY_CTX\s0\fR to \fB\s-1EVP_MD_CTX\s0\fR. This is usually used to provide
|
|
a customized \fB\s-1EVP_PKEY_CTX\s0\fR to \fIEVP_DigestSignInit\fR\|(3) or
|
|
\&\fIEVP_DigestVerifyInit\fR\|(3). The \fBpctx\fR passed to this function should be freed
|
|
by the caller. A \s-1NULL\s0 \fBpctx\fR pointer is also allowed to clear the \fB\s-1EVP_PKEY_CTX\s0\fR
|
|
assigned to \fBctx\fR. In such case, freeing the cleared \fB\s-1EVP_PKEY_CTX\s0\fR or not
|
|
depends on how the \fB\s-1EVP_PKEY_CTX\s0\fR is created.
|
|
.IP "\fIEVP_MD_do_all_provided()\fR" 4
|
|
.IX Item "EVP_MD_do_all_provided()"
|
|
Traverses all messages digests implemented by all activated providers
|
|
in the given library context \fIlibctx\fR, and for each of the implementations,
|
|
calls the given function \fIfn\fR with the implementation method and the given
|
|
\&\fIarg\fR as argument.
|
|
.SH "PARAMETERS"
|
|
.IX Header "PARAMETERS"
|
|
See \s-1\fIOSSL_PARAM\s0\fR\|(3) for information about passing parameters.
|
|
.PP
|
|
\&\fIEVP_MD_CTX_set_params()\fR can be used with the following \s-1OSSL_PARAM\s0 keys:
|
|
.ie n .IP """xoflen"" (\fB\s-1OSSL_PARAM_DIGEST_KEY_XOFLEN\s0\fR) <unsigned integer>" 4
|
|
.el .IP "``xoflen'' (\fB\s-1OSSL_PARAM_DIGEST_KEY_XOFLEN\s0\fR) <unsigned integer>" 4
|
|
.IX Item "xoflen (OSSL_PARAM_DIGEST_KEY_XOFLEN) <unsigned integer>"
|
|
Sets the digest length for extendable output functions.
|
|
It is used by the \s-1SHAKE\s0 algorithm and should not exceed what can be given
|
|
using a \fBsize_t\fR.
|
|
.ie n .IP """pad_type"" (\fB\s-1OSSL_PARAM_DIGEST_KEY_PAD_TYPE\s0\fR) <integer>" 4
|
|
.el .IP "``pad_type'' (\fB\s-1OSSL_PARAM_DIGEST_KEY_PAD_TYPE\s0\fR) <integer>" 4
|
|
.IX Item "pad_type (OSSL_PARAM_DIGEST_KEY_PAD_TYPE) <integer>"
|
|
Sets the pad type.
|
|
It is used by the \s-1MDC2\s0 algorithm.
|
|
.PP
|
|
\&\fIEVP_MD_CTX_get_params()\fR can be used with the following \s-1OSSL_PARAM\s0 keys:
|
|
.ie n .IP """micalg"" (\fB\s-1OSSL_PARAM_DIGEST_KEY_MICALG\s0\fR) <\s-1UTF8\s0 string>." 4
|
|
.el .IP "``micalg'' (\fB\s-1OSSL_PARAM_DIGEST_KEY_MICALG\s0\fR) <\s-1UTF8\s0 string>." 4
|
|
.IX Item "micalg (OSSL_PARAM_DIGEST_KEY_MICALG) <UTF8 string>."
|
|
Gets the digest Message Integrity Check algorithm string. This is used when
|
|
creating S/MIME multipart/signed messages, as specified in \s-1RFC\s0 3851.
|
|
It may be used by external engines or providers.
|
|
.SH "CONTROLS"
|
|
.IX Header "CONTROLS"
|
|
\&\fIEVP_MD_CTX_ctrl()\fR can be used to send the following standard controls:
|
|
.IP "\s-1EVP_MD_CTRL_MICALG\s0" 4
|
|
.IX Item "EVP_MD_CTRL_MICALG"
|
|
Gets the digest Message Integrity Check algorithm string. This is used when
|
|
creating S/MIME multipart/signed messages, as specified in \s-1RFC\s0 3851.
|
|
The string value is written to \fBp2\fR.
|
|
.IP "\s-1EVP_MD_CTRL_XOF_LEN\s0" 4
|
|
.IX Item "EVP_MD_CTRL_XOF_LEN"
|
|
This control sets the digest length for extendable output functions to \fBp1\fR.
|
|
Sending this control directly should not be necessary, the use of
|
|
\&\f(CW\*(C`EVP_DigestFinalXOF()\*(C'\fR is preferred.
|
|
Currently used by \s-1SHAKE\s0.
|
|
.SH "FLAGS"
|
|
.IX Header "FLAGS"
|
|
\&\fIEVP_MD_CTX_set_flags()\fR, \fIEVP_MD_CTX_clear_flags()\fR and \fIEVP_MD_CTX_test_flags()\fR
|
|
can be used the manipulate and test these \fB\s-1EVP_MD_CTX\s0\fR flags:
|
|
.IP "\s-1EVP_MD_CTX_FLAG_ONESHOT\s0" 4
|
|
.IX Item "EVP_MD_CTX_FLAG_ONESHOT"
|
|
This flag instructs the digest to optimize for one update only, if possible.
|
|
.IP "\s-1EVP_MD_CTX_FLAG_NO_INIT\s0" 4
|
|
.IX Item "EVP_MD_CTX_FLAG_NO_INIT"
|
|
This flag instructs \fIEVP_DigestInit()\fR and similar not to initialise the
|
|
implementation specific data.
|
|
.IP "\s-1EVP_MD_CTX_FLAG_FINALISE\s0" 4
|
|
.IX Item "EVP_MD_CTX_FLAG_FINALISE"
|
|
Some functions such as EVP_DigestSign only finalise copies of internal
|
|
contexts so additional data can be included after the finalisation call.
|
|
This is inefficient if this functionality is not required, and can be
|
|
disabled with this flag.
|
|
.SH "RETURN VALUES"
|
|
.IX Header "RETURN VALUES"
|
|
.IP "\fIEVP_MD_fetch()\fR" 4
|
|
.IX Item "EVP_MD_fetch()"
|
|
Returns a pointer to a \fB\s-1EVP_MD\s0\fR for success or \s-1NULL\s0 for failure.
|
|
.IP "\fIEVP_MD_up_ref()\fR" 4
|
|
.IX Item "EVP_MD_up_ref()"
|
|
Returns 1 for success or 0 for failure.
|
|
.IP "\fIEVP_DigestInit_ex()\fR, \fIEVP_DigestUpdate()\fR, \fIEVP_DigestFinal_ex()\fR" 4
|
|
.IX Item "EVP_DigestInit_ex(), EVP_DigestUpdate(), EVP_DigestFinal_ex()"
|
|
Returns 1 for
|
|
success and 0 for failure.
|
|
.IP "\fIEVP_MD_CTX_ctrl()\fR" 4
|
|
.IX Item "EVP_MD_CTX_ctrl()"
|
|
Returns 1 if successful or 0 for failure.
|
|
.IP "\fIEVP_MD_CTX_set_params()\fR, \fIEVP_MD_CTX_get_params()\fR" 4
|
|
.IX Item "EVP_MD_CTX_set_params(), EVP_MD_CTX_get_params()"
|
|
Returns 1 if successful or 0 for failure.
|
|
.IP "\fIEVP_MD_CTX_settable_params()\fR, \fIEVP_MD_CTX_gettable_params()\fR" 4
|
|
.IX Item "EVP_MD_CTX_settable_params(), EVP_MD_CTX_gettable_params()"
|
|
Return an array of constant \fB\s-1OSSL_PARAM\s0\fRs, or \s-1NULL\s0 if there is none
|
|
to get.
|
|
.IP "\fIEVP_MD_CTX_copy_ex()\fR" 4
|
|
.IX Item "EVP_MD_CTX_copy_ex()"
|
|
Returns 1 if successful or 0 for failure.
|
|
.IP "\fIEVP_MD_type()\fR, \fIEVP_MD_pkey_type()\fR" 4
|
|
.IX Item "EVP_MD_type(), EVP_MD_pkey_type()"
|
|
Returns the \s-1NID\s0 of the corresponding \s-1OBJECT\s0 \s-1IDENTIFIER\s0 or NID_undef if none
|
|
exists.
|
|
.IP "\fIEVP_MD_size()\fR, \fIEVP_MD_block_size()\fR, \fIEVP_MD_CTX_size()\fR, \fIEVP_MD_CTX_block_size()\fR" 4
|
|
.IX Item "EVP_MD_size(), EVP_MD_block_size(), EVP_MD_CTX_size(), EVP_MD_CTX_block_size()"
|
|
Returns the digest or block size in bytes.
|
|
.IP "\fIEVP_md_null()\fR" 4
|
|
.IX Item "EVP_md_null()"
|
|
Returns a pointer to the \fB\s-1EVP_MD\s0\fR structure of the \*(L"null\*(R" message digest.
|
|
.IP "\fIEVP_get_digestbyname()\fR, \fIEVP_get_digestbynid()\fR, \fIEVP_get_digestbyobj()\fR" 4
|
|
.IX Item "EVP_get_digestbyname(), EVP_get_digestbynid(), EVP_get_digestbyobj()"
|
|
Returns either an \fB\s-1EVP_MD\s0\fR structure or \s-1NULL\s0 if an error occurs.
|
|
.IP "\fIEVP_MD_CTX_set_pkey_ctx()\fR" 4
|
|
.IX Item "EVP_MD_CTX_set_pkey_ctx()"
|
|
This function has no return value.
|
|
.SH "NOTES"
|
|
.IX Header "NOTES"
|
|
The \fB\s-1EVP\s0\fR interface to message digests should almost always be used in
|
|
preference to the low level interfaces. This is because the code then becomes
|
|
transparent to the digest used and much more flexible.
|
|
.PP
|
|
New applications should use the \s-1SHA\-2\s0 (such as \fIEVP_sha256\fR\|(3)) or the \s-1SHA\-3\s0
|
|
digest algorithms (such as \fIEVP_sha3_512\fR\|(3)). The other digest algorithms
|
|
are still in common use.
|
|
.PP
|
|
For most applications the \fBimpl\fR parameter to \fIEVP_DigestInit_ex()\fR will be
|
|
set to \s-1NULL\s0 to use the default digest implementation.
|
|
.PP
|
|
The functions \fIEVP_DigestInit()\fR, \fIEVP_DigestFinal()\fR and \fIEVP_MD_CTX_copy()\fR are
|
|
obsolete but are retained to maintain compatibility with existing code. New
|
|
applications should use \fIEVP_DigestInit_ex()\fR, \fIEVP_DigestFinal_ex()\fR and
|
|
\&\fIEVP_MD_CTX_copy_ex()\fR because they can efficiently reuse a digest context
|
|
instead of initializing and cleaning it up on each call and allow non default
|
|
implementations of digests to be specified.
|
|
.PP
|
|
If digest contexts are not cleaned up after use,
|
|
memory leaks will occur.
|
|
.PP
|
|
\&\fIEVP_MD_CTX_name()\fR, \fIEVP_MD_CTX_size()\fR, \fIEVP_MD_CTX_block_size()\fR,
|
|
\&\fIEVP_MD_CTX_type()\fR, \fIEVP_get_digestbynid()\fR and \fIEVP_get_digestbyobj()\fR are defined
|
|
as macros.
|
|
.PP
|
|
\&\fIEVP_MD_CTX_ctrl()\fR sends commands to message digests for additional configuration
|
|
or control.
|
|
.SH "EXAMPLES"
|
|
.IX Header "EXAMPLES"
|
|
This example digests the data \*(L"Test Message\en\*(R" and \*(L"Hello World\en\*(R", using the
|
|
digest name passed on the command line.
|
|
.PP
|
|
.Vb 3
|
|
\& #include <stdio.h>
|
|
\& #include <string.h>
|
|
\& #include <openssl/evp.h>
|
|
\&
|
|
\& int main(int argc, char *argv[])
|
|
\& {
|
|
\& EVP_MD_CTX *mdctx;
|
|
\& const EVP_MD *md;
|
|
\& char mess1[] = "Test Message\en";
|
|
\& char mess2[] = "Hello World\en";
|
|
\& unsigned char md_value[EVP_MAX_MD_SIZE];
|
|
\& unsigned int md_len, i;
|
|
\&
|
|
\& if (argv[1] == NULL) {
|
|
\& printf("Usage: mdtest digestname\en");
|
|
\& exit(1);
|
|
\& }
|
|
\&
|
|
\& md = EVP_get_digestbyname(argv[1]);
|
|
\& if (md == NULL) {
|
|
\& printf("Unknown message digest %s\en", argv[1]);
|
|
\& exit(1);
|
|
\& }
|
|
\&
|
|
\& mdctx = EVP_MD_CTX_new();
|
|
\& EVP_DigestInit_ex(mdctx, md, NULL);
|
|
\& EVP_DigestUpdate(mdctx, mess1, strlen(mess1));
|
|
\& EVP_DigestUpdate(mdctx, mess2, strlen(mess2));
|
|
\& EVP_DigestFinal_ex(mdctx, md_value, &md_len);
|
|
\& EVP_MD_CTX_free(mdctx);
|
|
\&
|
|
\& printf("Digest is: ");
|
|
\& for (i = 0; i < md_len; i++)
|
|
\& printf("%02x", md_value[i]);
|
|
\& printf("\en");
|
|
\&
|
|
\& exit(0);
|
|
\& }
|
|
.Ve
|
|
.SH "SEE ALSO"
|
|
.IX Header "SEE ALSO"
|
|
\&\fIEVP_MD_meth_new\fR\|(3),
|
|
\&\fIopenssl\-dgst\fR\|(1),
|
|
\&\fIevp\fR\|(7),
|
|
\&\s-1\fIOSSL_PROVIDER\s0\fR\|(3),
|
|
\&\s-1\fIOSSL_PARAM\s0\fR\|(3)
|
|
.PP
|
|
The full list of digest algorithms are provided below.
|
|
.PP
|
|
\&\fIEVP_blake2b512\fR\|(3),
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\&\fIEVP_md2\fR\|(3),
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\&\fIEVP_md4\fR\|(3),
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\&\fIEVP_md5\fR\|(3),
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\&\fIEVP_mdc2\fR\|(3),
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\&\fIEVP_ripemd160\fR\|(3),
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\&\fIEVP_sha1\fR\|(3),
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\&\fIEVP_sha224\fR\|(3),
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\&\fIEVP_sha3_224\fR\|(3),
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\&\fIEVP_sm3\fR\|(3),
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\&\fIEVP_whirlpool\fR\|(3)
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|
\&\*(L"Fetching algorithms\*(R" in \fIprovider\fR\|(7)
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|
.SH "HISTORY"
|
|
.IX Header "HISTORY"
|
|
The \fIEVP_MD_CTX_create()\fR and \fIEVP_MD_CTX_destroy()\fR functions were renamed to
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\&\fIEVP_MD_CTX_new()\fR and \fIEVP_MD_CTX_free()\fR in OpenSSL 1.1.0, respectively.
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.PP
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|
The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
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|
later, so now \fIEVP_sha1()\fR can be used with \s-1RSA\s0 and \s-1DSA\s0.
|
|
.PP
|
|
The \fIEVP_dss1()\fR function was removed in OpenSSL 1.1.0.
|
|
.PP
|
|
The \fIEVP_MD_CTX_set_pkey_ctx()\fR function was added in 1.1.1.
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|
.PP
|
|
The \fIEVP_MD_fetch()\fR, \fIEVP_MD_free()\fR, \fIEVP_MD_up_ref()\fR, \fIEVP_MD_CTX_set_params()\fR
|
|
and \fIEVP_MD_CTX_get_params()\fR functions were added in 3.0.
|
|
.SH "COPYRIGHT"
|
|
.IX Header "COPYRIGHT"
|
|
Copyright 2000\-2019 The OpenSSL Project Authors. All Rights Reserved.
|
|
.PP
|
|
Licensed under the Apache License 2.0 (the \*(L"License\*(R"). You may not use
|
|
this file except in compliance with the License. You can obtain a copy
|
|
in the file \s-1LICENSE\s0 in the source distribution or at
|
|
<https://www.openssl.org/source/license.html>.
|